Cellular wireless technologies, such as cdma2000 and Universal Mobile Telecommunication System (UMTS), are expected to provide high speed wireless Internet connectivity to mobile users over a wide coverage area. At the same time, WLAN technologies, such as IEEE 802.11 and European HiperLAN, are becoming increasingly popular, as they provide a low cost and high speed wireless access solution for localized “hot spots”. According to one prediction regarding the future of mobile networking, wide area cellular networks and WLANs will complement each other to provide mobile users with ubiquitous high-speed wireless Internet connectivity. In such an environment the mobile users can be expected to experience a need to seamlessly switch between the WLAN and the cellular network, even during an ongoing Internet session.
Mobile terminals, also referred to herein as mobile nodes, that combine different radio interfaces, such as cellular and WLAN, in one device will be available soon. Further, the development of mobility aware Internet protocols has picked up pace in recent years. These and other factors will combine and converge in the near future to provide enhanced mobile user features and connectivity. This will, however, require that the inter-technology handoff issues and problems be addressed and resolved., such as the inter-technology handoff from a WLAN to a cellular network. In particular, when the mobile node moves from WLAN to cellular network coverage it has been found that the WLAN signal fades very fast. As a result, the time and signal margin available for execution of handoff or handover procedures is very small.
The Internet Engineering Task Force (IETF) has developed a Mobile IP protocol to enable IP-layer handoffs during an ongoing Internet session. To minimize disruption to the mobile node's Internet connectivity during such handoffs, protocols such as Fast Handoff and Context Transfer are also under development. While these protocols provide the core framework for seamless inter-technology handoffs, additional effort is required to apply them to specific environments. Further, these protocols assume the existence of a “trusting” relationship between the source (e.g., WLAN) and destination (e.g., cdma2000) access networks, which is not always the case.